Bending is a method of producing shapes by deforming the metal beyond its yield point
which is the material's capability to resist permanent deformation but not past its ultimate tensile strength
which is the metal's ability to resist tearing. The forces applied during bending are in opposite directions just as in shearing
the bending forces. However, rest between the material's yield point and its tensile strength in cheering
The forces used are well above the material's tensile strength. As the part is bent
it undergoes a distortion so that the material outside the bend is forced to stretch under tension and the material inside the bend is
forced to compress between the tension and compression zones is an area where the material is neither forced to stretch nor to compress
This is called the neutral axis. The neutral axis is important since bending operations are calculated from its location
the extent to which a material deforms, whether in compression or tension is proportional to the materials perpendicular distance from the neutral axis
The principal terms used to describe bending on press breaks are bend allowance
bend angle, bend radius and spring back, bend allowance is the prebent length of material
that must be included in a blank to allow for any deformation that occurs due to the bending operation
The bend angle is usually the included angle of the bent workpiece
It can also refer to the supplementary angle formed by the two bent tangent lines
The bend radius is a tangent line where the flat straight section of the part stops and the radius of the bend begins spring
back is the tendency of the material to return to its original form
Spring back typically ranges from 2 to 4 degrees